I made this to check whether the X, Y & Z
axes on my printer are set-up correctly.

I have made this part with a notch at 50mm on all axes and and an
overall length on all axes of 100mm. I figured this would allow me to
see if any inaccuracy got worse as the travel increased, i.e, is the
%age error at 50mm the same as at 100mm.

To get dimensionally accurate printouts the
printer has to be calibrated appropriately. I found that my Ultimaker
had some issues reproducing technical models accurately leading to
issues with fit of screw holes, etc.

This calibration piece allows to adjust the X,Y and Z-STEPS
appropriately.